THE SCIENTIFIC METHOD

(FOR OLDER GRADES OR INTERESTED PARTIES)

A scientific method is simply an orderly method for investigating a problem or observing a process. A scientific method is an important part of the process of scientific investigation. While the results of an investigation are important, it is impossible to tell if the results are accurate without knowing how the investigation was done. Were the correct items tested? Were there controls? Was the experiment repeated with the same results? All of these questions need to be answered to establish the correctness of the measurements and results. All experiments must have two key parts: variables and measurements.

Variables: There are three different types of variables.

1. Manipulated Variable: This is the one thing you will change in your experiment. (e.g. if you wanted to know how temperature affects the life of batteries, the temperature of the batteries being tested is the only variable that you would change.)

2. Responding Variable: This is the thing that changes as a result of the changes in the manipulated variable. (To continue with the example above: if you were testing the batteries in a flashlight, the responding variable would be the length of time the flashlight would work with batteries that had been kept at different temperatures.)

3. Controlled Variables: Sometimes called controls, these are all the things that you will keep the same in your experiment. (Controls in the battery example would be the brand and size of battery, the date on the package indicating shelf-life, the kind of flashlight used, the length of time each battery had been kept at each temperature, and anything else that might affect the results.)

Measurements: By taking measurements of the responding variable, you know how much change has occurred. In conducting an experiment, it is better to measure changes that involve differences in time, distance, height, and so on - things you can measure in numbers. Sometimes, you may want to “measure” things by just looking at them and observing change. However, measurements in numbers is best if possible.

So, What Is the Scientific Method Anyway? Here are the steps:

1. Select a Question you can answer by conducting an experiment. Use the library for ideas and information. You will find commonly done experiments, but you may also get some ideas about new topics and how to set-up your own experiment. Your question should be asked in such a way that it cannot be answered with a simple yes or no. For example, “How does salt affect the freezing point of water?” is a better question than “Does salt affect the freezing point of water?”

2. Form a Hypothesis: This is a prediction about what will happen as a result of your experiment. Forming a hypothesis will help you design your procedure, and the experiment will prove or disprove your hypothesis.

3. Perform the Experiment: Plan the details of your experiment. Select the manipulated and responding variables. Decide what things you must keep the same - these are your controls.

a. Determine what you will be measuring and what instrument you will use.

b. Select the materials to form the test equipment. Plan how the tests will be done. (Which test will you do first? How many tests will you do? What will be recorded? How many times will each test be repeated?)

c. Assemble the equipment to be used in the experiment.

d. Prepare data sheets for recording measurements and for your comments. As you perform the tests, enter all measurements on your data sheets. Take careful notice of what happens and write down what you observe. It is best to repeat each test a few times to be sure of your results.

4. Prepare the Results: Group and organize the measurements you have made. Make charts, graphs, and/or tables to show what happened. Wherever possible, use numbers to show your results. If one measurement is very different form all the others, check your comments to be sure that nothing unusual happened to that test. For example, if you were testing the effect of temperature change on batteries and you dropped the flashlight, your results from that test might not be accurate. Try to understand the problem so that you can explain unusual results.

5. Explain the Results: It is a good idea to spend some time thinking about your results and talking to other people about them. Think about what the charts, tables, and your comments mean. Note patterns and amounts. Try to explain how or why the results came out as they did. What was the cause? Do the results agree with your hypothesis?

6. Draw conclusions: What can you say about your experiment in general? What can you count on happening again if someone else does a similar experiment? Again note patterns and amounts in your conclusions. If possible, try to describe how your results might apply to everyday experiences. For example, in the battery experiment, you might decide that it is better to store extra batteries in the refrigerator or freezer.

An Added Note About Choosing An Experiment:

Be Creative: Creativity is an important element of any science experiment. Students are encouraged to try a new way of testing something or to design a procedure in a better or unusual fashion. Even if you are not sure a new method will work, give it a try as thinking of new and different things is something to celebrate, too!